IAS General Studies Prelims Question No. 91

A pesticide will generally undergo Bio-amplification in the food chain if __:
1. It is soluble in water
2. It is lipophilic
3. It is not easily degraded
Choose the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3

Answer

[B] Only 2 & 3
Any substance more soluble in tissue than the surrounding media has the tendency to concentrate in the food chain of more complex biological species that live on simpler biological species. So, in a nutshell, bio amplification occurs when concentrations of toxins are passed on from smaller prey to larger predators. There are two main groups of substances that biomagnify. Both are Iipophilic and not easily degraded. Novel organic substances are not easily degraded because organisms lack previous exposure and have thus not evolved specific detoxification and excretion mechanisms, as there has been no selection pressure from them. These substances are consequently known as ‘persistent organic pollutants’ or POPs. Metals are not degradable because they are elements. Organisms, particularly those subject to naturally high levels of exposure to metals, have mechanisms to sequester and excrete metals. Problems arise when organisms are exposed to higher concentrations than usual, which they cannot excrete rapidly enough to prevent damage. These metals are transferred in an organic form.

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